{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-04-06T14:01:22.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-04-06T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":628,"title":"Book Club","description":"A book club that has _K_ members, as a group, have to read _N_ books. Return how many different ways the members could read the books. All of the books must be read by at least one member of the group and all of the members must read one and only one book.\r\n\r\nFor Example, for _K_ = 3 and _N_ = 2, there are 6 ways\r\n\r\n# Member 1 reads book 1, Member 2 reads book 1, Member 3 reads book 2\r\n# Member 1 reads book 1, Member 2 reads book 2, Member 3 reads book 1\r\n# Member 1 reads book 1, Member 2 reads book 2, Member 3 reads book 2\r\n# Member 1 reads book 2, Member 2 reads book 1, Member 3 reads book 1\r\n# Member 1 reads book 2, Member 2 reads book 1, Member 3 reads book 2\r\n# Member 1 reads book 2, Member 2 reads book 2, Member 3 reads book 1\r\n\r\nNote: all of the test cases use small values of n and k to allow for brute-force solutions.","description_html":"\u003cp\u003eA book club that has \u003ci\u003eK\u003c/i\u003e members, as a group, have to read \u003ci\u003eN\u003c/i\u003e books. Return how many different ways the members could read the books. All of the books must be read by at least one member of the group and all of the members must read one and only one book.\u003c/p\u003e\u003cp\u003eFor Example, for \u003ci\u003eK\u003c/i\u003e = 3 and \u003ci\u003eN\u003c/i\u003e = 2, there are 6 ways\u003c/p\u003e\u003col\u003e\u003cli\u003eMember 1 reads book 1, Member 2 reads book 1, Member 3 reads book 2\u003c/li\u003e\u003cli\u003eMember 1 reads book 1, Member 2 reads book 2, Member 3 reads book 1\u003c/li\u003e\u003cli\u003eMember 1 reads book 1, Member 2 reads book 2, Member 3 reads book 2\u003c/li\u003e\u003cli\u003eMember 1 reads book 2, Member 2 reads book 1, Member 3 reads book 1\u003c/li\u003e\u003cli\u003eMember 1 reads book 2, Member 2 reads book 1, Member 3 reads book 2\u003c/li\u003e\u003cli\u003eMember 1 reads book 2, Member 2 reads book 2, Member 3 reads book 1\u003c/li\u003e\u003c/ol\u003e\u003cp\u003eNote: all of the test cases use small values of n and k to allow for brute-force solutions.\u003c/p\u003e","function_template":"function y = bookclub(n,k)\r\n  y = n^k-1;\r\nend","test_suite":"%%\r\nn = 4;\r\nk = 6;\r\ny_correct = 1560;\r\nassert(isequal(bookclub(n,k),y_correct))\r\n\r\n%%\r\nn = 3;\r\nk = 6;\r\ny_correct = 540;\r\nassert(isequal(bookclub(n,k),y_correct))\r\n\r\n%%\r\nn = 3;\r\nk = 5;\r\ny_correct = 150;\r\nassert(isequal(bookclub(n,k),y_correct))","published":true,"deleted":false,"likes_count":3,"comments_count":4,"created_by":134,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":21,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2012-04-26T19:36:01.000Z","updated_at":"2026-01-20T14:07:42.000Z","published_at":"2012-04-26T19:36:01.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eA book club that has\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eK\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e members, as a group, have to read\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eN\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e books. Return how many different ways the members could read the books. All of the books must be read by at least one member of the group and all of the members must read one and only one book.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFor Example, for\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eK\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e = 3 and\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eN\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e = 2, there are 6 ways\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 1, Member 2 reads book 1, Member 3 reads book 2\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 1, Member 2 reads book 2, Member 3 reads book 1\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 1, Member 2 reads book 2, Member 3 reads book 2\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 2, Member 2 reads book 1, Member 3 reads book 1\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 2, Member 2 reads book 1, Member 3 reads book 2\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 2, Member 2 reads book 2, Member 3 reads book 1\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eNote: all of the test cases use small values of n and k to allow for brute-force solutions.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"errors":[],"problems":[{"id":628,"title":"Book Club","description":"A book club that has _K_ members, as a group, have to read _N_ books. Return how many different ways the members could read the books. All of the books must be read by at least one member of the group and all of the members must read one and only one book.\r\n\r\nFor Example, for _K_ = 3 and _N_ = 2, there are 6 ways\r\n\r\n# Member 1 reads book 1, Member 2 reads book 1, Member 3 reads book 2\r\n# Member 1 reads book 1, Member 2 reads book 2, Member 3 reads book 1\r\n# Member 1 reads book 1, Member 2 reads book 2, Member 3 reads book 2\r\n# Member 1 reads book 2, Member 2 reads book 1, Member 3 reads book 1\r\n# Member 1 reads book 2, Member 2 reads book 1, Member 3 reads book 2\r\n# Member 1 reads book 2, Member 2 reads book 2, Member 3 reads book 1\r\n\r\nNote: all of the test cases use small values of n and k to allow for brute-force solutions.","description_html":"\u003cp\u003eA book club that has \u003ci\u003eK\u003c/i\u003e members, as a group, have to read \u003ci\u003eN\u003c/i\u003e books. Return how many different ways the members could read the books. All of the books must be read by at least one member of the group and all of the members must read one and only one book.\u003c/p\u003e\u003cp\u003eFor Example, for \u003ci\u003eK\u003c/i\u003e = 3 and \u003ci\u003eN\u003c/i\u003e = 2, there are 6 ways\u003c/p\u003e\u003col\u003e\u003cli\u003eMember 1 reads book 1, Member 2 reads book 1, Member 3 reads book 2\u003c/li\u003e\u003cli\u003eMember 1 reads book 1, Member 2 reads book 2, Member 3 reads book 1\u003c/li\u003e\u003cli\u003eMember 1 reads book 1, Member 2 reads book 2, Member 3 reads book 2\u003c/li\u003e\u003cli\u003eMember 1 reads book 2, Member 2 reads book 1, Member 3 reads book 1\u003c/li\u003e\u003cli\u003eMember 1 reads book 2, Member 2 reads book 1, Member 3 reads book 2\u003c/li\u003e\u003cli\u003eMember 1 reads book 2, Member 2 reads book 2, Member 3 reads book 1\u003c/li\u003e\u003c/ol\u003e\u003cp\u003eNote: all of the test cases use small values of n and k to allow for brute-force solutions.\u003c/p\u003e","function_template":"function y = bookclub(n,k)\r\n  y = n^k-1;\r\nend","test_suite":"%%\r\nn = 4;\r\nk = 6;\r\ny_correct = 1560;\r\nassert(isequal(bookclub(n,k),y_correct))\r\n\r\n%%\r\nn = 3;\r\nk = 6;\r\ny_correct = 540;\r\nassert(isequal(bookclub(n,k),y_correct))\r\n\r\n%%\r\nn = 3;\r\nk = 5;\r\ny_correct = 150;\r\nassert(isequal(bookclub(n,k),y_correct))","published":true,"deleted":false,"likes_count":3,"comments_count":4,"created_by":134,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":21,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2012-04-26T19:36:01.000Z","updated_at":"2026-01-20T14:07:42.000Z","published_at":"2012-04-26T19:36:01.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eA book club that has\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eK\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e members, as a group, have to read\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eN\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e books. Return how many different ways the members could read the books. All of the books must be read by at least one member of the group and all of the members must read one and only one book.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFor Example, for\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eK\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e = 3 and\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:i/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eN\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e = 2, there are 6 ways\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 1, Member 2 reads book 1, Member 3 reads book 2\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 1, Member 2 reads book 2, Member 3 reads book 1\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"2\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eMember 1 reads book 1, Member 2 reads book 2, Member 3 reads book 2\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId 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